Loud-speaking telephone-receiver.



C. ADAMS-RANDALL.

LOUD SPEAKING TELEPHONE RECEIVER.

APPLICATION FILED MAY 16, 1913.

1,083,788, H Pa ented Jan.6,1914.

m 19 M Wm CHARLES ADAMS-RANDALL, OF BOSTQN, MA$SACHUSETTS.

LOUD-SPEAKING TELEPHONE-RECEIVER.

To all whom it may concern Be it known that T, CHARLES ADAMS-RAN- BALL, a citizcnof the United States, residing at Boston, in the county of Sufiolk and State of Massachusetts, have invented certain new and useful Improvements in Loud Speaking Telephone-Receivers; and I do hereby declare the following to be a full,

clear, and exact description of the inven tion, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to telephone rev ceivers, and has for its object to provide a loud speaking electric telephone receiver which will bemore eflicient in action and therefore more satisfactory in use than those heretofore proposed. That is to say, heretofore a large class of receivers have been constructed with an electromagnet associated with a permanent magnet, as well as sometimes without the permanent magnet. But the magnetic means employed have been usually inclosed in a suitable case, upon the outer, open end of which a magnetic armature or diaphragm has been arranged in close proximity to the pole-ends of the magnet and firmly clamped to the case by means of a suitable ear-piece, without employing a resonator. lln such arrangements, the diaphragm is vibrated by the variations of the magnetic field in which it is held. Such vibrations, of course, cause a vibration of the air between the diaphragm and the ear, and the volume of sound is generally found sufiicient for commercial the receiver is held sufiiciently close to the ear. But such volume is not as great as is desired under all conditions, and many do 1 vices have been tried for augmenting the volume of the tones thus produced, to the end that the reproduced sounds may be heard ,Chief among these at greater distances. v devices are the well known horns or megaphones or" various forms and material. There are serious objections, however, to the megaphone as generally made and used, for although the volume or" tone is in some in stances increased,. its clearness and naturalness is generally impaired; and especially is this the case in the reproduction of articu; late speech, for here the minor vibrations are lost and the articulate words distorted thereby giving a tog-horn effect, so that the reproduction is neither clear, natural,

nor distinct.

Specification of Letters Patent.

urposes provided Patented Jan. 6,1914%;

Application filed ma 1c, 1913. Serial No. 768,053.

To overcome these serious and well known defects, while providing a commercially practical instrument is among the objects of this invention.

To this end, the invention involves more particularly a construction comprising the well known magnet of the telephone receiver, and a suitable resonator, in which the diaphragm, armature, or vibrator forms a part of or coacts with the said resonator.

The resonator thus takes the place of a megaphone and serves to reproduce the words or sounds transmitted, more naturally and clearly and with a greater volume than has been possible heretofore.

The diaphragm .forming a part of the resonator, may be a magnetic plate of any desired 'form, or it may be composed of a series of magnetized wires of the same or of different diameters or lengths, or it may consist of both classes of wires, so they will have different rates of vibration. l/Vith such a construction, .the changes of the density of the magnetic field, and of the magnetic waves are more faithfully set up in the diaphragm, and the resulting air waves of speech and other sounds are reproduced withtheir natural characteristics.

The operation of this invention may be likened to that or a violin, in which the resonator or body of the violin is set in vibration by the manual vibration of its strings, the resonator or the body of the violin, augmenting greatly the volume of tone, while at the same time preserving all of the charac teristics of each string and the notes produced by the fingering. ln'this invention the vibrations of the resonator are produced electro-inagnetically through the diaphragm, and on the principles above stated, the volume of sound is increased, while the characteristics of the vibrations are preserved.

Referring to the accompanying drawings forming a part of this specification, in which like numerals designate like parts in all the viewsFigure l is a diagrammatic plan view partly broken away of a receiver ice - 2, I attachto the resonator body 1 the bent supports 2, 2, of wood, aluminum or other suitable material, and I preferably place wooden blocks or washers 3 between said supports and resonator as shown. Screw members 4 passing through said washers .and supports serve-to adjustably hold the latter to the resonator body. The said supports are provided with the slots 5 to facilitate their adjustment relative to the screws 4, as shown. Any suitable guiding means 5 may, if desired, be employed to. govern the up and down movement of the said supports 2. Also attachedjto the resonator are one or more sounding posts 6 similar to like members employed in violins and similar instruments.

On the top of the resonator 1, I suitably secure a magneto telephone receiver 7 preferably of the type called watch case and in which there is assembled a plurality of permanent magnets 8 having the pole pieces 9. On these pole pieces' there is further attached the electromagnet 10 having the poles 11. Suitably attached to the. supports 2., is the plate diaphragm 12, which is so positioned as to lie just above and in close proximity to said pole pieces 11. I prefer to employ diaphragms of different lengths, or diameters, when circular diaphragms are used, and to this end I provide clamping plates 13 adapted to be adjusted and held to the supports 2 by means of the screws 14, entering the different sets of holes 15, 16 and 17. By this means diaphragm plates 12 of any desired area may'beused. It will now be clear that the electromagnetic vibrating means comprising the magnet 10 is permanently attached to the sounding box, as well as the diaphragm 12, so that any vibrations'that may be imparted to the lat ter will be reinforced by the said box or resonator .1.

..In the modified form of construction shown in Figs. 3 and 4 the diaphragm is composed of a plurality of magnetized wires 18 of' difierent sizes asshown. In this case each wire will have a tendency to vibrate in unison with an air wave of its own period, and therefore the whole diaphragm is adapted 4 escapes to pick up reproduced waves of difierent periods and to reinforce them by means of the sound box. A cushion 19 which may be of leather or other material is preferably interposed between the members 13 and 18 as shown. I

It is obvious that those skilled in the art may vary the details of construction as well as the arrangement of parts without departing from the spirit of my invention and therefore I do not wish to be limited to the above disclosure except as may be required by the claims.

VVhatI claim is v 1. In a loud speaking telephone receiver, the combination of a resonator; a diaphragm comprising a plurality of wires having different periods of vibration and of magnetic 1 material rigid with said resonator; magnetic means rigidly associated with said resonator and diaphragm; and means for adjusting the relation between said magnetic means and said diaphragm, substantially as described.

2. In a loud speaking telephone receiver, the combination of a box-like resonator; a pair of supports adjustably secured to said resonator; a diaphragm carried by said supports; means associated with said supports for adjusting and clamping said diaphragm thereon; and an electromagnet rigidly attached to said resonator in operative relation withsaid diaphragm, substantially as described.

3. In a loud speaking telephone receiver, the combination of a box-like resonator; a pair of supports .adjustably secured to said resonator; a diaphragm composed of-a plurality of magnetic wires of different dianr eters carried by said supports; means associated with said supports for adjusting and clamping said diaphragm thereon; and an electromagnet rigidly attached to said resonator in operative relation with said diaphragm, substantially as described.

In testimony whereof I afiiX my signature in presence of two witnesses.

CHARLES ADAMS-RANDALL.

Witnesses:

CHAS. C. DASEY, (Ms. J. OCoNNoR. 

